A gas turbine power plant and a combined cycle power plant are used as a power plant that provides industrial electrical power. It is known that when the gas turbine power plant or the combined cycle power plant is operated in summer or at a high ambient temperature, the air intake quantity of a compressor is smaller than when the plant is operated at a low ambient temperature. Such a relative decrease in the intake air quantity of the compressor results in a decrease in power output and in thermal efficiency.
A regenerative cycle gas turbine power plant disclosed, for instance, in Patent Document 1 increases both the power output and thermal efficiency of the gas turbine power plant. This regenerative cycle gas turbine power plant cools intake air by spraying the upstream of a compressor with fine water drops and increases the power output by raising the temperature of humidified air by using the exhaust gas of a gas turbine as a heat source.